ca.pfv.spmf.algorithms.sequentialpatterns.prefixSpan_AGP

Class AlgoPrefixSpan_AGP

java.lang.Object

ca.pfv.spmf.algorithms.sequentialpatterns.prefixSpan_AGP.AlgoPrefixSpan_AGP

public class AlgoPrefixSpan_AGP
extends java.lang.Object

This is an implementation of the PrefixSpan algorithm by Antonio Gomariz Peñalver(AGP). PrefixSpan was proposed by Pei et al. 2001. This algorithm was inspired in the implementation of SPMF and, from it, I changed and optimized some things.

NOTE: This implementation saves the pattern to a file as soon as they are found or can keep the pattern into memory if no output path is provided by the user.

Constructor Summary

Constructors

Constructor and Description
AlgoPrefixSpan_AGP(double minsupRelative, AbstractionCreator creator) Standard constructor.

Method Summary

Modifier and Type	Method and Description
void	clear() It clears all the attributes of AlgoPrefixSpan class
double	getAbsoluteMinSupport() It gets the absolute minimum support, i.e.
int	getNumberOfFrequentPatterns() Get the number of frequent patterns found.
long	getRunningTime() It gets the time spent by the algoritm in its execution.
java.lang.String	printStatistics() Method to get the outlined information about the search for frequent sequences by means of PrefixSpan algorithm as a string.
void	runAlgorithm(SequenceDatabase database, boolean keepPatterns, boolean verbose, java.lang.String outputFilePath) Method that starts the execution of the algorithm.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AlgoPrefixSpan_AGP

public AlgoPrefixSpan_AGP(double minsupRelative,
                          AbstractionCreator creator)

Standard constructor. It takes the minimum support threshold (from 1 up to 0) and an abstraction creator

Parameters:

minsupRelative - the relative minimum support threshold

creator - the abstraction creator

Method Detail

runAlgorithm

public void runAlgorithm(SequenceDatabase database,
                         boolean keepPatterns,
                         boolean verbose,
                         java.lang.String outputFilePath)
                  throws java.io.IOException

Method that starts the execution of the algorithm.

Parameters:

database - The original database in which we apply PrefixSpan

keepPatterns - Flag indicating if the user want to keep the frequent patterns or he just want the amount of them

verbose - Flag for debugging purposes

outputFilePath - Path pointing out to the file where the output, composed of frequent patterns, has to be kept. If, conversely, this parameter is null, we understand that the user wants the output in the main memory

Throws:

java.io.IOException

printStatistics

public java.lang.String printStatistics()

Method to get the outlined information about the search for frequent sequences by means of PrefixSpan algorithm as a string.

Returns:

a string

getNumberOfFrequentPatterns

public int getNumberOfFrequentPatterns()

Get the number of frequent patterns found.

Returns:

the number of frequent patterns.

getRunningTime

public long getRunningTime()

It gets the time spent by the algoritm in its execution.

Returns:

the time spent (long).

getAbsoluteMinSupport

public double getAbsoluteMinSupport()

It gets the absolute minimum support, i.e. the minimum number of database sequences where a pattern has to appear

Returns:

the minimum support (double)

clear

public void clear()

It clears all the attributes of AlgoPrefixSpan class